To construct the outlook on great quality, the concept of quality can be divided into two aspects, micro quality and macro quality at present. However, the definition of micro quality and its contents are not related organically with the conception of macro quality and its contents. So an intermediate variable between micro quality and macro quality is needed to link them together, and this intermediate variable is named as medium quality. This paper introduces the connotation of medium quality that includes the concept of quaternary quality, namely zero quality, unary quality, binary quality and ternary quality, and explains the progressive logical relationships of these four qualities. Micro quality and macro quality are cohered by medium quality organically, and thus formulates the scientific outlook on great quality.